Do you have any recommended parts suppliers, or conversely, ones you'd recommend staying away from?
Having just purchased my Malibu I unfortunately do not have any recommended suppliers at this point. I will be happy to share my experiences when they take place.
Is a dyno a prerequisite or would a couple runs at the local strip suffice well enough?
What are the desired goals?
Often times spending more time learning to become a better driver should be goal number one if you are looking for performance times. There are many professional associations you can join and performance driving classes you can attend. But if you really are John Force by all means move on to modding your car. In this case yes a couple of runs will suffice. A dyno number will not guarantee any quarter mile time.
Now if he had a specific horsepower goal in mind, he would certainly need to visit the dyno. I would suggest this before any mods to the car are done. If you don't have a baseline run, how do you know if you have really added/subtracted power? Tuning needs can also be addressed here.
With the 3.6 rated at 252 HP (not sure if it's BHP or crankshaft) approx. how much boost would it take to raise it to around 300-325?
That number is certainly crankshaft hp. Please do not be disappointed when you dyno your car if it reads much lower than that. Are you familiar with the difference between the two numbers?
A wide variety of factors would go into your approximate boost question. There are a thousand different turbos that would generate a thousand different answers, all at a thousand different elevations. Not all turbos are the same size. Not all turbos are designed the same. Your turbocharger is just one of many variables in this equation, too.